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The controllable synthesis of carbon nanofibers (CNF) and composites based on CNF (Metals/CNF) is of particular interest. In the present work, the samples of CNF were produced via ethylene decomposition over Co-Pt (0–100 at.% Pt) microdispersed alloys prepared by a reductive thermolysis of multicomponent precursors. XRD analysis showed that the crystal structure of alloys in the composition range of 5–35 at.% Pt corresponds to a fcc lattice based on cobalt (Fm-3m), while the CoPt (50 at.% Pt) and CoPt3 (75 at.% Pt) samples are intermetallics with the structure P4/mmm and Pm-3m, respectively. The microstructure of the alloys is represented by agglomerates of polycrystalline particles (50–150 nm) interconnected by the filaments. The impact of Pt content in the Co1−xPtx samples on their activity in CNF production was revealed. The interaction of alloys with ethylene is accompanied by the generation of active particles on which the growth of nanofibers occurs. Plane Co showed low productivity (~5.5 g/gcat), while Pt itself exhibited no activity at all. The addition of 15–25 at.% Pt to cobalt catalyst leads to an increase in activity by 3–5 times. The maximum yield of CNF reached 40 g/gcat for Co0.75Pt0.25 sample. The local composition of the active alloyed particles and the structural features of CNF were explored. [ABSTRACT FROM AUTHOR]

X-ray diffraction (XRD) pattern of nanosized equimolar solid solution CoIr prepared by thermolysis of [Co(NH3)6][Ir(C2O4)3] contains peaks characteristic of both face-centered cubic (fcc) and hexagonal close-packed (hcp) structure. Moreover, 101 peak of hcp modification is substantially wider than 100 and 002 peaks, 102 and 103 are very broad and almost invisible. Peak 200 of fcc structure is wider than the other peaks of this modification and slightly shifted toward lower angles. It was shown by simulation of XRD patterns that particles of CoIr alloy are nanoheterogeneous and consist of lamellar domains having fcc and hcp structures. The best fit was obtained for the following model parameters: an average crystallites size is about 10 nm, average thicknesses of the fcc and hcp domains are 1.7 and 1.1 respectively. The presence of domain structure was confirmed by transmission electron microscopy data. [ABSTRACT FROM AUTHOR]

The platinum–gold alloyed nanoparticles were prepared via decomposition of double complex salts containing both inorganic and organic ligands. Decomposition of the precursor was performed in a reductive atmosphere with varied temperature ramping rates. The samples were characterized by means of X-ray diffraction (XRD) analysis, transmission electron microscopy, and UV–vis spectroscopy. According to XRD data, both the ramping rate and the final temperature of decomposition strongly affect the Pt–Au ratio in alloyed nanoparticles which are being formed. The average crystallite size was found to be 15–20 nm, that was also confirmed by UV–vis spectroscopy for the alloyed Pt–Au nanoparticles supported on alumina. [ABSTRACT FROM AUTHOR]

Double complex salts of rhodium(III) and gold(III) of the composition [Au(en) 2 ][Rh(NO 2 ) 6 ]·2H 2 O ( 1 ) and [Au(en) 2 ][Rh(NO 2 ) 6 ] ( 2 ) have been prepared. Crystal structures of the compounds have been determined by single crystal X-ray diffraction. The compounds have been characterized by PXRD, IR, far-IR, CHN and DTA. The complexes have a layered structures. The presence of water in 1 makes the structure of the hydrated DCS less dense as compared to the anhydrous one. The environment of the cation and the anion in the two structures is the same, oxygen atoms of the nitro groups are involved in hydrogen bonds N–H⋯O, N⋯O distances being approximately the same. The structures of 1 and 2 are notable in having shortened contacts between the gold atoms and the oxygen atoms of the nitro groups of the neighboring complex anions. The thermal behavior of the complexes in a hydrogen atmosphere was investigated. The final product of thermolysis prepared at the temperature 600°С is a two-phase mixture of pure metallic gold and the solid solution Rh 0.93 Au 0.07 . [ABSTRACT FROM AUTHOR]

The Ni-Pt phase diagram was corrected in the range of 15–85 at.% Pt and in the temperature range of 400–525 °C using powder X-ray diffraction data. To reduce the time required to achieve the equilibrium state, Ni-Pt alloys, consisting of 80–140 nm nanocrystalline particles (nanoalloys) were used as initial samples. The nanoalloys were synthesized by thermolysis of specially prepared multicomponent precursors. Phase transformations in the system at high temperatures were studied in situ by X-ray diffraction. The boundary positions of Ni 1−x Pt x (A1), Ni 3 Pt (L1 2), NiPt (L1 0), NiPt 3 (L1 2) single-phase regions were corrected. [Display omitted] • Phase equilibria in the Ni-Pt system was experimentally reinvestigated. • The formation processes of Ni 3 Pt and NiPt intermetallic phases were studied in situ. • The NiPt 3 single-phase region was significantly corrected. • Proposed the corrected Ni-Pt phase diagram. [ABSTRACT FROM AUTHOR]